1. Field of the Invention
The present invention relates to a method and device for bending an exposed core wire of an electric cable for effecting a firm and tight connection with a terminal lug.
2. Description of the Prior Art
U.S. Pat. No. 3,668,764 issued to Randar on Jun. 13, 1972 shows an example of the prior art method in which an exposed core wire of the electric cable is bent back along the cable surface, and then a terminal lug is applied around the end portion of the stripped end so that the exposed core wire is electrically held in contact with the terminal lug.
As shown in FIG. 2, a clamping unit 11 clamps the electric cable P which has an end portion which has been stripped of the coating member to expose a core wire A. The core wire A is brought under a punch 12.
As shown in FIG. 3, as the punch 12 goes down, the core wire A is bent downwardly. Then the punch 12 and an anvil 13 are moved substantially parallel to the axis of the cable P, and then a terminal lug B is moved and guided along a U-groove of the anvil 13.
While the terminal lug B is moved, the downwardly bent core wire A is further bent back by the terminal lug B in a U-shape, as shown in FIG. 4. Then, a crimper 14 goes down to crimp the terminal lug B to locate the bent back core wire A between the terminal lug B and the insulating member of the cable P, as shown in FIG. 5.
However, as shown in FIG. 6, according to the prior art as described above, the bent portion of the core wire A may returned by its resiliency, resulting in the wire bending at the mid-point of the stripped wire portion in response to the backward movement of the lug B. In this case, a firm electric contact between the terminal lug B and the core wire A can not be ensured.
Also, as shown in FIG. 7, when the core wire A hangs down due to its resiliency, the core wire A may be undesirably cut by the edge of terminal lug B.
The above of problems are often observed in a wrapped type of electric cable P, such as shown in FIG. 8. The wrapped type electric cable P is formed by a tension member 1 made of aramid fibers. A core 2 of thermoplastic material is mounted on tension member 1 and a resistant wire (conductor) 3 is spirally wound around the core 2. An insulator 4 and sheath 5 are further mounted on the core 2 and the resistant wire 3.
As a result of such construction, when the wrapped cable P is stripped of the insulator 4 and sheath 5 by a given length from the end for a bending operation as shown in FIG. 2, the core wire A is different to bend but easily returns to the straight state because the core wire A in this case is made of tension member 1, core 2 and resistant wire 3 having a high elasticity. Thus, the above described problems are often observed. It is to be noted that both of the insulator 4 and sheath 5 hereinafter will be referred to as the "insulating coating".